Although Exadata is Oracle's most popular and mature "engineered system," some customers implementing the database machine are making mistakes that prevent them from getting the most performance out of the expensive product, according to a veteran of many Exadata projects.

Many people have seen Oracle's advertisements that sing Exadata's praises and cite astounding-sounding performance improvements over running the same workload on traditional hardware, said Andy Colvin, practice director with Oracle consulting firm Enkitec, during a presentation at the Collaborate conference in Las Vegas last week.

A lot of databases are hindered because they're running on servers with older hardware and fibre channel interconnects, as well as a shared SAN (storage area network). Exadata targets these problems with features such as dedicated storage and Infiniband interconnects.

"You get away from everybody else," Colvin said. "You get to be the kid with your own sandbox, so you're not sharing storage with the rest of the organization."

Maybe as a result of this, some customers "think of [Exadata] as throwing hardware at a problem, and it's really not," Colvin said. Simply moving workloads over to Exadata will typically result in a three-times performance improvement, he added.

A few key moves are highly important. For one, Exadata can benefit from a smaller SGA (system global area), Oracle's name for the shared RAM space used by a database instance. "If you start small it will recognize you have a small buffer cache," he said. "It's going to utilize all that power you have down at the storage tier."

But in general, new Exadata customers should realize they "aren't special," and avoid making too many arbitrary tweaks, Colvin said. "You've got a nice fancy system Oracle has configured and tested."

Meanwhile, it might even be a big mistake to buy Exadata at all, as it could be overkill, according to another presenter at Collaborate.

Automotive parts manufacturer Gentex is running its substantial ERP (enterprise resource planning) system with a combination of commodity servers and storage, said Cliff Burgess, director of IT at the company.

It went with the combination after getting the hard sell from Oracle on an Exadata upgrade. The solution Gentex ultimately came up with ended up involving far less additional hardware than Oracle's representatives claimed it would, according to Burgess.

Oracle customers who need more performance would be well served to determine whether simply some faster chips, additional RAM and solid-state cards would solve their problems, versus buying an Exadata, he added.

That advice comes as Oracle's sales organization is placing heavy emphasis on Exadata and other engineered systems, versus commodity boxes. Oracle recently passed the 10,000 mark for sales of engineered systems, CEO Larry Ellison said during the company's third-quarter earnings call last month.

For Oracle, engineered systems represent a much more lucrative opportunity than the hardware alone, given they get loaded with plenty of high-margin software licenses that subsequently generate annual maintenance revenue streams.

All things to consider when the Oracle Exadata salesman comes calling, according to Burgess.

"Don't let Oracle come in and sell you the shiny box," he said. "As a customer, I don't want what's best for Oracle, I want what's best for me."